This chapter is from the book

Wireless technology is changing the world. Where communication has
hitherto relied on cables strung on poles or dug into the ground, we are now
able to send voice and data through air and empty space. Without wires holding
us back, we will be able to stay in contact wherever we are. New services can be
set up in minutes, without spending months negotiating rights of way or
constructing tunnels.

The preceding paragraph could have been written a hundred years ago. At the
beginning of the twentieth century, wireless technology also promised to
revolutionize communications. It did, but it took many decades before it could
be combined with another of the twentieth century's new
technologiestelephony. A second wireless revolution occurred in the 1990s
as wireless transmitters became small and lightweight enough to be built into
hand-held telephones. Rather than simply watching TV or listening to radio, the
majority of people in some countries were broadcasting signals of their
own.

The effects of this second revolution continue into the 2000s, as both
wireless technology and telephony converge with the Internet. The result may
eventually be a single network for both voice and data, with wireless as the
dominant access method. Most information will still travel over high-bandwidth
fiberoptic cables for parts of its journey, but the phones and computers through
which people actually interact with the network will not require wires.

What's in a Name?

Wireless technology is littered with three-letter acronyms (TLAs). Those that
appear in this book are spelled out when first used and sometimes again in later
chapters. They are also listed and defined in the glossary.

A few are impossible to spell out; this is because some vendors and standards
groups develop a kind of "acronym envy" over the capital letters that
acronyms usually use. These people insist that their technologies be
capitalized, even though they don't actually stand for anything.

Still more vendors like to take an existing acronym, often one of an official
standard, and change or add one letter (often m, for mobile). This
is an attempt by companies to differentiate themselves from the
competition, but it has the opposite resultmany very similar-sounding
products or standards.

The situation is further complicated by the way that certain acronyms change
over time. For example, the basic cellular standard in the United States is
called AMPS, which originally stood for Advanced Mobile Phone
System. As technology progressed, it began to seem anything but
advanced, so the A changed to Analog. When a digital version was
developed, it changed again to the more accurate American. All three are
still in use.

The terms cell phone and mobile phone mean almost the same and
are often used interchangeably. Technically, cellular is a subset of
mobile, but a large one: Most mobile systems are cellular, and all
cellular systems are mobile. In general, the British tend to say mobile,
whereas the Americans say cell. The industry prefers mobile,
because it implies freedom, whereas cell suggests imprisonment. A
few companies don't like the term phone, because newer devices are
more like small computers. For this reason, they are often referred to as
terminals.

One advantage of cellular/mobile telephony is that it can compete with
monopoly wireline phone companies. These monopolies are known by a
variety of names, not all of them printable, but are officially called
Incumbent Local Exchange Carriers (ILECs, or simply incumbents), because
they own the telephone exchange. In the United States, they are sometimes called
Regional Bell Operating Companies (RBOCs), after the Bell system from
which they are descended. In most other countries, they're called
Post, Telegraph, and
TelecommunicationsAuthorities (PTTs), because they used to
be (and in some cases still are) run by the country's Post Office.

Cutting the Cables

The wireless revolution cuts both ways: It changes the Internet and the phone
system, but also requires change in the wireless technology itself. Digitization
and Internet protocols enable radio to carry much greater amounts of data than
its nineteenth-century pioneers thought possible, all personalized for
individual listeners. Instead of poor-quality television programs broadcast to
everyone, users may eventually have virtual reality on demand.

By mid-2000, more people in Europe had a mobile phone than had a PC or a car.
By the end of 2001, the world's most popular online service was one that
could be accessed only through a cell phone, not a computer. Analysts
predict that the trend will continue, with wireless gadgets overtaking
traditional computers as the dominant Internet access means at some point
between 2004 and 2006. Unlike the relatively primitive, text-based Internet
phones that appeared in 2000, these new gadgets will allow true Web surfing, as
well as location-based services and other enhancements that take
advantage of mobility.

This shift from fixed to mobile access could have profound effects on the
Internet, which, in its early years, was dominated mainly by the wealthy, the
young, and the male. That will change: Mobile phones are more evenly distributed
across society, and even the cheapest models are beginning to incorporate some
kind of Internet access. Though these cost slightly more to produce, operators
often subsidize the manufacturing to promote usage.

And wireless technology isn't just for rich consumers in the West. In
the late 1990s, cell phones enabled many people all over the world to make their
first-ever calls. In the next few years, they will also be sending their first
e-mailsagain, wirelesslyand probably from something that more
closely resembles a phone than a traditional PC. The Web will become truly
worldwide.

Most of the excitement is justifiably about mobile wireless, but there
are also significant advancements in fixed wireless, which is used to
replace local telephone wires. Satellite systems can be either mobile or fixed,
with some systems, such as the futuristic Teledesic, planning both. These are
aimed both at globe-trotting travelers and at parts of the world that have no
communications infrastructure at all. A combination of cellular and satellite
technology can often bring telephony and Internet access to areas that
would have to wait many years for cables.

Network Philosophies

In the wired world, boundaries between networks are quite clearly defined:
Whoever owns the cables or the devices connected to them controls the network.
There are generally two types:

Wide Area Networks (WANs) cover a long distance, from several
kilometers to the entire world or beyond. They are usually run by telecom
companies and carry voice or data for various customers. The Internet and the
phone system are both comprised of many WANs. They are often called
public networks, because they carry traffic for anyone who can pay. (In
this case, public does not refer to ownership: Whether owned by a
government, a traded corporation, or a private individual, a network that
carries traffic for others is considered public.) WANs are sometimes
divided into subgroups, of which, the most important is the MAN
(Metropolitan Area Network), a type that covers a city or other region of only a
few kilometers. Because radio waves have a limited range, most wireless WANs are
MANs. The exceptions are satellite networks, which can cover intercontinental
distances.

Local Area Networks (LANs) cover only a short distance, usually
100 m or less. They are usually installed within homes or offices and are
accessible only to the residents or employees. For this reason, they are
referred to as private networks. The PAN (Personal Area Network)
is a special case of a wireless LAN, with a particularly short range. It can
cover a distance of only 10 m and is envisaged as a way to connect devices
carried by a single individual.

In the wireless world, the distinctions between LAN and WAN or between public
and private networks are less clearly defined. Radio waves don't respect
legal boundaries or even physical walls, meaning that private transmissions can
spill over into the public space. The first effect of this has been to expose
private data to all comers, thanks to unencrypted wireless LANs. In the future,
it could change how people access the Internet or make phone calls.

The companies that run wireless networks want people to use the public WAN.
Their vision of the future is something similar to that shown in Figure 1.1,
where each wireless device has its own separate, long-distance connection. This
means that users have to pay the companies for access and that the devices can
be used almost anywhere. A cell phone user can travel many miles while making a
call, often without the connection being broken.

Many people have an alternative vision, shown in Figure 1.2. This uses a
small LAN access point within the home or office, connected via a fixed network
to the Internet and the phone system. Cordless phones and wireless-equipped
computers communicate with the access point, which aggregates all their voice
and data together and sends it over a single connection. The advantage of this
is that it's cheaperone connection costs less than manyand can
achieve higher data rates, thanks to the shorter range of the wireless signal
and the high capacity of the fixed network. The disadvantage is that the phones
and computers can't be carried out of range of the access point while
maintaining a connection.

For narrowband voice, the WAN philosophy seems to be winning: Many people in
Europe have a mobile as a "primary" phone, using it for all calls,
even when at home. The same is beginning to happen in North America, though only
for long-distance calls. This is partly because the cell phone is more
convenient and partly because aggressive competition keeps cell phone
charges relatively cheap, whereas fixed telephony is often run by a de
facto monopoly.

For broadband data, the situation is reversed. No WAN technologies can yet
match the speed of wireless LANs, so many people prefer to set up their own
wireless LAN and connect it to some kind of high-speed fixed-access technology.
This is usually a cable in the ground, as shown in the figure, but in
future may be a point-to-point wireless system, such as a laser beam. It's
also possible that the WAN and LAN will converge as mobile operators set up
wireless access points of their own.

Cell Phone Generations

The present hype is around third-generation (3G) phones, which will
provide most of the advanced services planned until at least 2010. But it's
worth looking at the other generations and the features they offer:

1G. First-generation phones are analog, meaning that they
send information as a continuously varying wave form. They can be used only for
voice and have highly variable call quality, thanks to interference. Another
serious disadvantage is that they are very insecure; snoopers can listen in
on calls with a simple radio tuner or can even charge calls to another
person's account.

Almost no new 1G networks are now built anywhere in the world, but the phones
to use with them are still manufactured. Europe and Japan both gave them up in
the 1990s, upgrading to digital systems. North America is not as far advanced,
but it's moving in the same direction: At the beginning of 2002, about 30%
of U.S. subscribers relied on 1G phones, down from twice as large a proportion
two years earlier. They are more popular in some parts of Africa and South
America, thanks to their low cost, but even there, they will soon be squeezed
out by second-generation (2G) and even 3G technology.

2G. Second-generation phones convert all speech into digital code,
resulting in a clearer signal that can be encrypted for security or
compressed for greater efficiency. Most also include some kind of simple text
messaging, as well as support for Centrex-style services, such as voice mail and
Caller ID. The most popular is the Global System for Mobile Communications
(GSM), but several others are used around the world. They can send data, but
usually at less than 10 kilobits per second (kbps); by comparison, most modems
achieve a real speed of at least 30 kbps. Some data-only devices, such as
two-way pagers, are also considered to be 2G, because they send a digital signal
at relatively low speeds.

Most cellular operators are upgrading their 2G networks to higher data
speeds, theoretically more than 100 kbps but more realistically those of a fast
modem (about 40 kbps or less). These are referred to as 2.5G, because
they are significantly better than existing 2G systems but less advanced than
the more futuristic 3G. As well as offering higher data rates, they often use
packet-switching for data, a more efficient way of sharing a connection
between many users. This is the same system used by the Internet, so it makes
interconnection between the phone and the Internet easier.

Some 2.5G upgrades don't try to reach higher data rates, instead adding
the capability for specific applications. Wireless Application Protocol (WAP)
and i-mode both use a compressed version of the Web to fit into a mobile
phone's slow data rate and small screen. Location technologies can find a
user's exact position, intended both for emergency calls and for services
such as maps.

3G. Third-generation systems will provide a variety of advanced
services, including data transfer at up to 2 megabits per second (Mbps) and
videoconferencing. Instead of phones, many terminals will be small computers or
PDAs (personal digital assistants) with built-in Web browsers and
possibly other applications, such as word processors, spreadsheets, and address
books. They will include small keyboards, handwriting recognition, and,
eventually, voice recognition.

Like many new technologies, 3G has initially been disappointing. The first
data rates of the first terminals are only 64 kbps, less than those once
envisaged for 2.5G, let alone 3G. Many companies admitted that the expected 2
Mbps would be available only for users standing right next to a base station
tower. These initial services are sometimes referred to as 3G lite. At
the other end of the scale, many researchers are working on enhancements to 3G
that they claim really will reach the hoped-for data rate and beyond. These are
known as 3.5G.

Many 3G terminals will also be able to link to a PAN, which links all the
devices in a very small area, such as a room or even a person's pocket. The
most promising technology for this is Bluetooth, which puts a very low-power
radio into a single microchip. Bluetooth's designers envisage a chip inside
almost all household devices, as shown in Figure 1.3, enabling them all to
connect to the Internet via a 3G terminal.

4G. Fourth-generation networks are already in the labs, with
Japanese operator NTT DoCoMo planning to offer the first commercial services in
2006. They will offer very high data rates, perhaps as much as 100 Mbps,
enabling new services that have not yet been invented. They will also be
focused primarily on data, using packet-switching for all traffic and
replacing basic voice service with video or even virtual reality.

Many wireless LAN technologies already come close to 4G's hoped-for data
rates, though they don't offer the service guarantees or roaming capability
that users of cell phones expect. If these can be added to wireless LANs, 4G may
actually arrive earlier than expected.